68 TRANSPORTATION RESEARCH RECORD 1317 Evaluation of Marshall and Hveem Mix Design Procedures for Local Use H. AL-ABDUL w AHHAB AND ZIA UDDIN A. KHAN Conventional methods of mix design can sometimes result in materials that do not perform satisfactorily. In countries that experience extremes of temperature such as Saudi Arabia, the resultant failures can be severe, often occurring soon after the road is opened to traffic. A laboratory evaluation of and Hvecm mix designs w<:is undectakcn with an objective of minimizin.g permanent deformation in asphaltic la yers. Five dif- ferent gradati n. were ·clcclccJ IJ<:i se cl on Mini try of Commu- nications specifications. The dcsig11 procedures were examined, and the mixes were subjected 1 dynamic and stali ' testing to evaluate re. ilient modulus. sp.lit tensile strength , stiffnes , and creep compliance characteristics. The test results indicated that Hveem mixes possessed b tter engineering properties than tho ·e designed by the Mar hull method because the 1-lvcem merh d can better identify mixe wirh hi gh rutting susceptibility. Rec- ommendations for additional testing techniques co ulc.J be used for both mix design and quality control purpo. Over the past two decades, Saudi Arabia has initiated massive construction programs to modernize and improve its highway network. In the short span of 20 years, Saudi Arabia has built an impressive highway network comparable to that of many developed countries. This network-which includes more than 3,600 km (2,200 mi) of divided highways, more than 30,000 km (18,600 mi) of paved roods, and thousands of bridges, some of which are marvels of engineering achievement-was built at a cost of more than 100 billion Saudi riyals ($27 billion) (1). Most of these roads have served for more than a decade, and a number of them have started to fall apart. The rate of deterioration of pavements has been augmented by increasing traffic and axle loads and a lack of good-quality materials. Roads are designed for lives of 15 to 20 years before they need any major maintenance. However, during the past few years these roads have experienced excessive failure (rutting) at an early stage of pavement life. The rutting problem, because of its extent and importance, has attracted the attention and care of many highway au- thorities. Khan et al. (2) pointed out that the requirements and specifications used in Saudi Arabia allow construction with mixtures susceptible to rutting because of the following factors: 1. Unlimited amount of natural sand, 2. Low voids in mineral aggregate (VMA), 3. High asphalt content, and 4. No measure of shear strength. H. Al-Abdul Wahhab, Civil Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. Z. A. Khan, Al-Muhandis Nizar Kurdi Consulting Engineers, P.O . Box 2962, Riyadh 11461, Saudi Arabia. Most asphaltic paving technologists and literature on the subject agree that for good performance asphaltic concrete must have high stability and durability values. For asphaltic concrete to have good stability (i.e., resistance to stress), it must have adequate strength in tension to prevent cracking and adequate strength in shear to prevent deformation or rutting. The literature has indicated that Hveem stability yields a measure of the angle cp (angle of internal friction in the Coulomb-Mohr equation), which furnishes resistance to rut- ting, and that the Marshall stability is a measure of c (cohesion in the Coulomb-Mohr equation) of tensile strength to resist cracking in pavement (3). Because the mix design procedure currently used in Saudi Arabia-the Marshall mix design-does not measure shear strength of the paving mixture, an attempt was made to ex- plore and evaluate other design procedures, such as the Hveem mix design method, and to compare their abilities to predict the strength properties of designed mixes (especially rutting resistance) and in-service performance using laboratory tests. Additional laboratory tests, such as static creep and resilient modulus, were used to characterize the mechanical properties of asphalt mix in order to predict the permanent deformation (rutting) that will occur when the mix is used in a pavement of given construction and subjected to the unique traffic load- ing and climatic conditions in Saudi Arabia. STUDY APPROACH A systematic study approach was important in order to achieve the study objectives. The study included three main inter- connected tasks. The first task was material collection and mix design. The second task involved laboratory testing and evaluation. The third task involved analyzing data and making conclusions, and recommendations. A schematic for the study approach is shown in Figure 1. The first task involved material characterization and the design of five mixes for five gradations according to the Min- istry of Communications (MOC) specification using the Mar- shall mix design method (ASTM D1159) and the Hveem mix design method (ASTM D1560 and ASTM D1561). These mixes were subjected to further characterization tests, such as the resilient modulus, split tensile, and static creep tests, in order to provide a better evaluation and basis for comparing the two mix design methods, to develop recommendations to im- prove local mix design, and to minimize the rutting problem on local roads.
Evaluation of Marshall and Hveem Mix Design Procedures for Local Use
Apr 22, 2023
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